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    <title>Document</title>
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<body>
    <script>
        // 题1：如何用闭包实现: 调用数组中第几个函数，就打印几
        let arr = []
        for (let i = 0; i < 5; i++) {
            arr[i] = function () {
                console.log(i)
            }
        }
        arr[3]();  // 3

        var arr1 = [];
        for (var i = 0; i < 5; i++) {
            (function (a) {
                arr1[a] = function () {
                    console.log(a);
                }
            })(i)
        }
        arr1[3](); // 3
    </script>
</body>

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